Improvement in damper-regulators for furnaces and stoves



A. c. NORCRO-SS.

DAMPER-REGULATOR FOR FURNACES AND STOVES. No. 178,944. Patented. June 20 1876.

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N. PETERS. PHOTO-LITNOGRAPHER, WASHINGTON, D, C. V

ALVIN O. NORCROSS, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN DAMPER-REGULATORS FOR FURNACES AND STOVESH' Specification forming part of Letters Patent No. 178,944, dated June 20, 1876; application filed April 13, 1876.

' hot-air or air-heating furnace provided with my invention. Fig.4 is a longitudinal section of its aut'omatic'heat or draft regulator.

Heretofore it has been customary to connect the automatic heat or draft regulator of a furnace either to a damper or valve arranged in the smoke-discharge flue of the fire-place or chamber of combustion, or to one arranged in an air-induct leading into the ash chamber or space beneath the grate of such furnace. Each of such arrangements of the valve or damper is objectionable. The difliculty attending the employment of a damper in the smoke-discharge pipe is that it, by reducing the passage for discharge of the smoke and waste gases, often checks their escape to such a degree as to cause them to be forced out of the doorway or any of the joints of the fireplace. -Attempts to regulate, by an automatic heat or draft regulator, the admission of air into the ashchamber or space beneath the grate of a furnace, generally fails, from the fact that the joints are not air-tight or cannot be maintained sufficiently tight.

In carrying out my invention, I lead out of the ashchamber or space beneath the-grate 0f the fire-place an educt or pipe, which I-open into the smoke-pipe ordischarge-fiue of the fire-place or chamber of combustion; and I place in such pipe or educt a valve or damper, and so connect it with the automatic heat or draft regulator as to enable the latter to work such valve or damper, the main object of such improvement being to regulate the draft through the fuel, by discharging by the educt,

" from the chamber below the grate, the surplus air not required for combustion. By so doing I am not obliged to have any door of the furnace fit thedoorway with a tight joint, or

to change or vary the heat-regulator so as to open the damper more, preparatory to opening the door of the fireplace or ash'chamber, whether for supplying the furnace with fuel or for removing ashes, or any other purpose, as is generally necessary when the damper is in the smoke discharge pipe or flue.

In the drawings, A denotes the fire-place, B the grate, C the ash-chamber, and I) the smoke-discharge fine of the fire-place or chamber of combustion, the air-heating chamber surrounding the fire-pot being shown at E. An automatic heat or draft regulator is represented at F, as arranged in the upper part of the air-heating chamber, and extending in opposite directions out of it. 7

Furthermore, there is led out of the ash chamber (J, or chamber beneath the grate, a pipe or'educt, G, which is extended to and opens into the smoke-discharge flue D, and is provided with a damper, H, from whose shaft or spindle a an arm, b, is extended, such arm being connected by a rod, 0, with the lever d of the heat -or draft regulator. The rod is jointed to the said arm and lever.

This automatic heat or draft regulator F, as shown in the drawings, may be thus described: Its case is composed of a metallictube 0, having at its front enda stopper or head, f, provided with a dial or index-plate, 9, through the axis of which'and the stopper ascrew, h, furnished with an index-pointer, c,

' is screwed against a metallic disk, k, arranged in the tube. There is also in the tube a cylinder or-rod, l, of wood, porcelain, or some other proper material, which at one end rests against the said disk It, and at the other, against another such disk, m. To the rearend of the tube 6 there is fixed a'case, n, for supporting a slider, 0, and two levers, p d, formed and arranged within the case, in manner as shown, the said levers being pivoted to the case.

As the air within the chamber E of the furnace may rise in temperature its heat will be communicated to thetube e, which, by such heat, will be expanded in a greater degree than will the cylinder 1, and, consequently, while the tube may be contracting the slider 0 will force the longer arm of, the shorter of 2 was) the two levers p d against that of the longer of them, and thereby cause this latter arm to heat of the furnace may rise above the point required, the damper will be opened, so as to allow a portion or all of the air that may enter the chamber beneath the grate to escape, by the exit-pipe thereof, into the smoke-dis charge pipe, without going through the grate and the fuel therein. I11 this way an indrat't is effected at every joint and a consequent escape of gas or smoke otherwise than into the smoke-flue is prevented, whether the door or doors be closed or openniore or less.

I would remark that, instead of leading the pipe G directly into the smoke-dischargeflue or pipe, such pipe Gr may open at its upper end into the fire-place or chamber of combustion over the grate. Also, that my invention is applicable to the furnacepf a steam-boiler, provided the heat or draft regulator be extended into the steam-space of the boiler.

Instead of the damper being in the pipe leading from theaslrchamber into the chamber of combustion or its smoke -discharge flue, such damper may be in an induct to lead air into the ash'chamber or space beneath the grate.

I claim- In combination with a stove or furnace and an automatic heat-regulator, F, applied thereto, a pipe or conduit, Gr, leading out of the ash-chamber or space'under the grate and communicating with the smoke-dischargepipe or flue D of the said stove or furnace, and provided with a damper, H, and mechanism ap 'llied-thereto, or connecting such and the heat regulator, to cause or enable the valve or damper to be automatically moved or operated by such heat-regulator, under variations of temperature, all being substantially as set forth.

ALVIN G. NORC-ROSS.

] Witnesses:

R. H. EDDY, J. R. SNOW. 

